Expert: Roland Finston - 8/10/2011

Question
I BOUGHT A 2000 DODGE NEON USED. IT RUNS GREAT. WHEN I COME TO A STOP THE IDLE RUNS A BIT ROUGH, SOMETIMES PUTTING IT IN NEUTRAL HELP THE IDLE. I HAD THE PLUGS, WIRES, OIL, TRANS FLUID, POWER FLUID, COOLANT, AIR filter replace. general stuff done. Why do you think i have a rough idle? how can i make it stop?

Answer
Hi Kim,
My thought is that you have an exhaust gas recirculation valve that is sticking slightly ajar when you come to a stop. It is supposed to close tightly when you slow down otherwise the mixture of air/fuel is too lean for a good idle. If you have an egr valve and can find it then you can try to fix it yourself with a spray can of WD-40 or similar spray solvent.
Now the issue is whether you have an egr valve. My '97 shop manual for the 2.0L engine shows there is one, but the '01 shop manual says there isn't one. So what is the case with your '00 is not certain. If you look on the sticker on the underside of the hood that shows the vacuum hose connections you could review that for the presence or absence of an "egr valve" in the diagram. Otherwise you can look at the rear of the engine underneath where the air intake hose is located to see if you see a round object with vacuum hoses attached to it.
Let me know what you find on the sticker and by looking at the engine.
You also could try the ignition key to see if there are any fault codes stored in the engine controller. Turn the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to be sure of an accurate set of flash counts. The last two sets will always be 5 and 5. Then let me know the counts and we'll go from there.

Roland